I would like to mark my emails in the inbox with different colors after I receive them. I know i can assign colors to emails based on who they came from. But I want to assign colors or some other marker after i receive the email. It should not matter who its from.

Basically I receive a lot of emails. Some require my response and some dont. I just want to make the email that requires my response look different in my inbox so I can remember to get to it when i have time. I usually skim through my email and dont necessarily have enough time sometimes to respond to them as soon as I receive them.